Circuit interrupter



R. E. FRIEDRICH 2,465,218

C IRCUIT INTERRUPTER March 22, 1949.

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Patented Mar. 22, 1949 CIRCUIT INTERRUPTER Robert E. Friedrich, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 21, 1946, Serial No. 711,422

9 Claims.

This invention relates to circuit interrupters, in general, and more particularly to arc extinguishing structures therefor.

High speed reolosing oil circuit breakers encounter diiiiculties where the first and second interruptions occur within or less cycles of each other. Conventional interruptions are handicapped inasmuch as the second interruption must confront contaminated gases and uid remaining from the first interruption. My improved interrupter is designed to improve the aforementioned situation by affording the gases remaining after the first interruption an enhanced opportunity to escape from the arc extinguishing structure and to be replaced by fresh oil from the tank, thus setting up the same conditions in the interrupter as existed before the first interruption.

The principal object of my invention is to provide an improved arc extinguishing structure suitable for rapid reclosing operations in which means i are provided to permit rapid circulation of fluid through the interrupter in the open circuit position thereof, so that contaminated uid will not be present within the interrupter for thesecond opening operation.

Another object is to provide an improved arc extinguishing unit of the type utilizing pressure and interrupting chambers in which port openings are provided controlled by valve means to permit ready circulation of fluid through the chambers in the open circuit :position of the interrupter.

Another object is to provide an improved arc extinguishing structure in which contact means is Cooperable to establish an lare andin which port openings are provided to eliminate contaminated fluid in the open circuit position of the interrupter.

Further objects and advantages will readily become apparent upon a reading of the following specification, taken in conjunction with the drawing, in which:

Figure 1 is a side elevational View, partially in section, of a circuit interrupter embodying my invention and shown in the closed circuit position;

Fig. 2 is an enlarged vertical sectional view through the left hand arc extinguishing unit of Fig. 1, the contacts being shown in the closed circuit position;

Fig. 3 is a sectional view taken along the line III-III of Fig. 2; and

Fig. 4 is a fragmentary view similar to Fig. 2 but showing the valve means in the freely open position.

Referring to the drawing, and more particularly to Fig. 1 thereof, the reference numeral I designates a tank in which a suitable arc eX- tinguishing iiuid 2, in this instance circuit breaker oil, fills the tank I to the level 3. Depending from the cover 4 of the tank I are two insulating bushings 5, 6 at the lower ends of which are rigidly secured identical arc extinguishing units, generally designated by the reference numeral 1. The two units 1 are electrically connected together in the closed circuit position of the interrupter, as shown in Fig. 1, by a conducting crossbar or operating bar 8 reciprocally operated in a vertical direction by an insulating operating rod 9, the latter being actuated by suitable mechanism, not shown.

Referring to Fig. 2, which shows more clearly the internal construction of the extinguishing unit l, it will be observed that I have provided a top dome casting Ill which is an integral part of a contact foot Il, the latter being threadedly secured and clamped to the lower end or" the terminal stud which extends interiorly through the terminal bushing 5. The top dome casting I0 defines a pressure-generating chamber generally designated by the reference numeral I2, in which a pivotally mounted pressure-generating contact I3 cooperates with an intermediate contact I4 to establish a pressure-generating arc. Cooperable with the intermediate contact I4 is a lower movable contact I5 secured to the end of the crossbar 8 and actuated thereby. An operating rod I6 extends longitudinally exteriorly of the unit 'I and is pivotally connected by a lost motion connection to the externally disposed actuating arms Il of the pivotally mounted pressure-generating contact I3, only one of which is shown in Fig. 2. The pressure contact I3 is pivotally mounted at I8 and is secured in place by a clamp plate I9 secured by bolts 20 to the housing or dome casting I0. A flange 2l is integrally formed with the operating rod I6 and servesk as a lower seat for a compression spring 22, the upper end of which is seated against a washer 23 slidable upon the rod I6 and making engagement with the lower ends 24 of the actuating arms II. The arms I'I have apertures 25 provided therein through which extends the pivot pin 25a, the latter being affixed to the upper end of the rod I6.

The rod I6 is biased downwardly in the circuit opening direction by means of a compression spring 26, the latter being seated upon a flange 21 integrally formed with the rod I6. The upper end of the compression spring 26 seats against the bottom metallic plate of the unit l. From the foregoing description it will be apparent that downward movement of the rod will initially merely cause downward movement of the Within the apertures 25 formed in the e; actuating arms Il, the washer Eil biasing the contacts I3 and i4 into engagement. However, wi

the pin 25a strikes the lower ends of the apertures 25, it will cause positive clockwise rotation of the pivotally mounted pressure-generating contact I3 upwardly away from the interme late contact iii to establish a pressure-generating arc within the pressure-generating chamber l2.

Substantially simultaneously with the separation of the contacts i3, I4, separation takes place between the upper end of the lower movable contact l and the lower end of the intermediate -contact i4 to establish an interrupting arc within the interrupting chamber, generally designated by the reference numeral E9, and formed by the superpositioning of a plurality oi suitably configured insulating plates. An insulating bushing Si) is provided in the plate to guide the lower contact l5, which is completely withdrawn from the contact opening 3l in the fully open circuit position of the interrupter, as shown by the dotted lines 32 of Fig. l.

The interrupting chamber 29 is more fully set forth and described in U. S. patent application, led November il, 1942, Serial No. 455,244 by Leon R. Ludwig, Winthrop IVI. Leeds and Benjamin P. Baker, now U. S. Patent 2,406,469, issued August 27, 1946, and assigned to the assignee of the instant application. This application also claims the pivotal connection between the operating rod l5 and the pressure Contact i3.

For the purpose of explaining my invention, it is merely neces-sary to state that fluid, in this instance oil, under pressure from the pressure arc within the pressure chamber l2, flows downwardly as indicated by the arrows 33 to flow radially inwardly toward the interrupting arc drawn between the contacts I4, i5 through a plurality, in this instance four, pairs of inlet passages 34 to engage the interrupting arc. After engaging the interrupting arc, the oil flows through orifices 35 longitudinally of the interrupting arc to exhaust out of the unit l through -oppositely directed exhaust passages 35, shown more clearly by the dotted lines of Fig. 3. The exhaust passages 35 are formed by the cooperation of a pair of vent plates 3l, 35 positioned on the same level.

To facilitate circulation of the oil through the interrupter in the fully open circuit position thereof, I have provided a nrst port opening 39 disposed adjacent to the pressure-generating chamber I2 at the upper end of the unit l. The rst port opening 39 is controlled by a first cylindrical valve member 49. I also provide a second port opening 4l disposed adjacent the interrupting chamber 29 at the lower end of the unit l which is controlled by a second cylindrical valve member 42. Preferably, I interconnect the first and second valve members 49, 42 by an insulating rod 43, and I provide biasing means such as a compression spring 44 to bias both valve members 40, 42 downwardly to thereby tend to cause opening of the i-lrst and second port openings 39, 4I.

The spring 44 seats at its upper end against a bracket 52 integrally formed with the contact foot Il. The lower end of the compression spring seats within a hollow portion 53 formed within the upper end of the cylindrical valve 49. A projection 54 formed by a plate 55 extends within a groove 56 of valve 42 and provides a stop for the downward opening travel of the valve means when it strikes the lower end 51 of valve 49. Actuating means for the valve means includes a valve rod 45 affixed to the lower end of the valve member 42 and making abutting engagement with a projection 45 of the crossbar 8.

I have provided improved flushing means by providing the large port openings 39, 4l in both the top and bottom of the unit 'I after interruption has occurred. The considerable pressure remaining in the pressure chamber l2 at the time when the port opening 39 is permitted to open blows contaminated oil out of the pressure chamber I2 through the port opening 39 and facilitates the replacement of fresh oil into the pressure chamber I2. When the interrupter is reclosed, these port opening-s 39, 4| are respectively -sealed off by the valve pistons 49, 42 mounted on the actuating means or rod 45 which is engaged by the breaker crossbar 8 and biased toward the open position by the compression spring 44. The rod 45 remains in abutting engagement with the crossbar 8 during the opening operation by virtue of compres-sion spring 44 until the stop 54 is struck by upper valve member 49. The open position of the valve members 49, 42 is shown by Fig. 4. It is preferable, and the illustrated construction is such, that the port openings 39, 4l are not opened until the movable contact l5 withdraws from the contact opening 3l. This provides the desired pressure within the unit 'I during the interruption process.

It will be apparent that in the open circuit position of the interrupter, as shown by the dotted lines 32 of Fig. 1 and in Fig. 4, the provision of two port openings 39, 4l will permit ciroulation of fresh oil into the unit l and upwardly through the vertical ow passages 50 toward the pressure chamber I2 and out through the upper port opening 39. This facilitates circulation of fresh oil into the unit 1 in the open circuit position thereof and washes out contaminated liquid to thereby provide fresh oil of high dielectric ystrength for the next circuit opening operation.

From the foregoing description, it will be apparent that I have provided an improved circuit interrupter especially adapted for rapid reclosing operations by eliminating the contaminated liquid within the extinguisher in the open circuit position thereof.

Although I have shown and described a specific structure, it is to be clearly understood that the same was merely for the purpose of illustration and that changes and modifications may readily be made therein by those skilled in the art without departing from the spirit and scope of the appended claims.

I claim as my invention:

l. In a circuit interrupter of the liquid break type, a substantially enclosed arc extinguishing unit immersed in the liquid, Contact means inciuding a movable contact for establishing atleast one arc within the unit, an opening in the wall of the unit, means for moving the .movable contact out of the unit through the opening in the fully open circuit position of the interrupter, a relatively large first opening in the wall of the unit adjacent one end thereof, a relatively .large second opening in the wall of the unit adjacent the other end thereof, relatively free passage means connecting the said first and second openings, and valve means closed in the closed position of the interrupter and responsive to the initial opening movement oi the movable contact 'for opening the iirst and second openings only after Withdrawal of the movable contact through the first-mentioned opening to permit circulation oi fluid through the unit.

2. In a circuit interruptor of the iiquid break type, a substantially enclosed arc extinguishing unit, means for establishing a pressure-generating arc and an interrupting arc Within the unit, a relatively large first opening in the wall or" the unit disposed adjacent to the pressure-generating arc, a relatively large second opening in the Wall of the unit disposed adjacent to the interrupting arc, and Valve means closing the said openings in the closed position of the interrupter openN ing the rst and second openings in the fully open circuit position of the interrupter.

3. In a circuit interrupter of the liquid blast type, means at least partially of insulating material defining an arc extinguishing unit, means defining a confined pressure-generating chamber disposed at one end ci the unit, defining an interrupting chamber disposed adjacent the other end of the unit, an opening in the unit disposed adjacent the said other end of the unit, means for establishing a pressure-generating arc within the pressure-generating chamber, means including a movable contact movable out of the said opening for establishing an interrupting arc Within the interrupting chamber, a relatively large iirst port opening in the Wall or the unit adjacent the pressure-generating chamber, a relativey large second port opening in the Wall of the unit adjacent the interrupting chamber, and valve means closing the said port openings in the closed position of the interrupter and responsive to the initial movement or the movable Contact for opening the rst and second port openings in the fully' open circuit position oi the interrup-ter.

4. In a circuit interrupter of the liquid break type, an arc extinguishing unit having two port openings in the Walls thereof disposed adjacent opposite ends or the unit, an opening in the wall of the unit, contact means including a moi/able contact for establishing an arc within the unit, a crossbar secured to the movable Contact to cause the actuation thereof out of the unit through the said opening, the crossbar having a projection thereon, valve means including a valve rod for opening the two port openings in the open circuit position of the interrupter, and the projection of the crossbar controlling the initial movement of the valve rod during the opening operation.

5. In a circuit interruptor of the liquid break type, means deiining an arc extinguishing unit, a pressure chamber and an interrupting chamber within the unit, an exhaust passage leading out of the interrupting chamber to the region exterior of the unit, a contact opening in the wall oi the unit, contact means including a movable contact movable out of the contact opening for establishing an interrupting arc Within the interrupting chamber, means for establishing a pressuregenerating arc Within the pressure chamber, passage means interconnecting the two chambers, relatively large first and second port openings in the Walls of the unit disposed respectively adjacent the pressure and interrupting chambers, and valve means closing the port openings in the closed position of the interruptor and controlling the opening of the two port openings in response to opening movement of the movable contact.

6. In a circuit interruptor of the liquid break type, an arc extinguishing unit immersed in an arc extinguishing liquid, means defining a pressure-generating chamber disposed at one end of the unit, means dening an interrupting chamber disposed at the other end of the unit, a rst port opening disposed in the Wall of the unit adjacent the pressure-generating chamber, a second port opening disposed in the Wall of the unit adjacent the interrupting chamber, means for establishing a pressure-generating arc Within the pressure-generating chamber, contact means including a movable contact movable out of the unit during the opening operation for establishing an interrupting arc within the interrupting chamber', valve means for controlling the opening ci the iirst and second port openings, actuating means for the valve means responsive to the initiai motion of the Contact means, means bias ing the valve means to the open position, and the actuating means maintaining the valve means closed in the closed circuit position of the interrupter against the biasing action exerted by the biasing means.

7. In a circuit interrupter of the liquid break type, an arc extinguishing unit immersed in an arc extinguishing liquid, means defining a pressure-generating chamber disposed at one end of the unit, means defining an interrupting chamber disposed at the other end of the unit, a iirst port opening disposed in the Wall of the unit adjacent the pressure-generating chamber, a second port opening disposed in the wall or the unit adjacent the interrupting chamber, means for establishing a pressure-generating arc within the pressuregenerating chamber, a contact opening provided in the Wall oi the unit adjacent the interrupting chamber, contact means including a movable contact movable out of the unit through the Contact opening durirrr the opening operation for establishing an interrupting arc Within the interrupting chamber, valve means for controlling the opening oi the first and second port openings, actuating means for the valve means responsive to the initial motion of the contact means for delaying the opening oi the rst and second port openings until the movable contact has Withdrawn from the unit through the contact opening, means biasing the valve means to the open position, and the actuating means .maintaining the valve means closed in the closed circuit position of the interruptor against the biasing action exerted by the biasing means.

8. In a circuit interrupter of the liquid break type, an arc extinguishing unit immersed in an arc extinguishing liquid, means dening a pressure-generating chamber disposed at one end of the unit, means denning an interrupting chamber disposed at the other end of the unit, a rst port opening disposed in the wall oi the unit adjacent the pressure-generating chamber, a second port opening disposed in the Wall of the unit adjacent the interrupting chamber, means for establishing a pressure-generating arc within the pressure-generating chamber, a contact opening provided in the wall of the unit adjacent the inter-A rupting chamber, an operating bar, contact means including a movable contact secured to the operating bar for establishing an interrupting arc within the interrupting chamber, the operating bar withdrawing the movable Contact out of the contact opening in the fully open circuit position of the interruptor, valve means for controlling the opening of the first and second port openings, means biasing the valve means to the open position, actuating means for the valve means including a Valve rod making abutting engagement with a portion of the operating bar, and the operating bar maintaining the Valve means `closed in the closed circuit position of the interrupter against the biasing action exerted by the biasing means.

9. In a circuit interrupter of the liquid break type, an arc extinguishing unit immersed in an arc extinguishing liquid, means` defining a pressure-generating chamber disposed at one end of the unit, means dening an interrupting chamber disposed at the other end of the unit, a first port opening disposed in the wall oi the unit adjacent the pressure-generating chamber, a second port opening disposed in the `wall of the unit adjacent the interrupting chamber, means for establishing a pressure-generating arc within the pressure-generating chamber, a contact opening provided in the wall of the unit adjacent the interrupting chamber, an operating bar, contact means including a movable contact secured to the operating bar for establishing an interrupting arc within the interrupting chamber, the operating bar withdrawing tne movable Contact out of the contact opening in the fully open circuit position of the interrupter, valve means for controlling the opening of the rst and second port openings, means biasing the Valve means to the open position, actuating means for the valve means including a Valve rod making abutting engagement with a portion of the operating bar, the operating bar maintaining t'ne valve means closed in the closed circuit position oi the interrupter against the biasing action exerted by the biasing means, and the arrangement being such that the valve means does not open the two port openings until the movable Contact has withdrawn from the contact opening during the opening operation of the interrupter.

ROBERT E. FRIEDRICH.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Number Name Date 1,144,047 Merriam June 22, 1915 2,134,569 MacDonald et al. Oct. 25, 1938 2,389,346 Denault Nov. 20, 1945 2,409,723 Terry Oct. 22, 1946 2,420,888 Leeds May 20, 1947 

